The 400-year period of oppression and slavery

• Start — Genesis 15:13. The year the 400-year period of oppression began is the year it ended at the Exodus (2515) - the 400 years it occurred = 2115
• End — Genesis 15:13. The year the 400-year period of oppression ended is the year of the Exodus = 2515

START:This period of oppression began with Ishmael mocking Isaac at the feast to celebrate Isaac's weaning (GEN 21:8-9) at age 5. [Shulman date p45] [Ussher date p26] END:[Shulman date p45]

Years are anno hominis — counted from Creation as year 1 — which is the frame the source computes in. The arithmetic behind each boundary is given above rather than assumed.